Decorative miniature lights such as miniature Christmas lights are assembled into light strings and, the typical arrangement has the lights connected in a series circuit. Although these light strings are relatively easy and inexpensive to manufacture, certain drawbacks and shortcomings are inherent in the design most common to the art. Since the light string is connected in series, the failure of a single bulb in the string will open the circuit and simultaneously cause all the other bulbs in the string to fail.
Attempts to prevent string failure in series circuit light strings have included the use of a single shunt in association with each bulb and socket combination. The single shunt is typically positioned directly within the glass envelope of each bulb in the string, making the effectiveness of the shunt depend on the presence at all times of a bulb within each of the bulb sockets in the string. In operation, the shunt provides an alternate path through which electric current will flow in the event of bulb failure. After bulb failure and as long as the bulb remains in the string, the shunt allows current to continue to flow through the bulb, thereby maintaining the circuit in a closed condition to prevent the failure of the entire light string.
Single shunts of the type mentioned above, however, have not been entirely satisfactory. For example, when a bulb in the string is crushed during installation or shipping, the bulb shunt is often damaged or broken and, thereafter, is ineffective in preventing string failure. Additionally, during installation of a light string on a Christmas tree, for example, bulbs on the string are often twisted, causing the lead wires of the bulb to either break or to move off of the electrical terminals within the socket. Since these events will interrupt the flow of current through the bulb and damage the associated shunt, the placement of a single shunt within the bulb envelope has been ineffective in preventing the failure of the entire light string under the aforementioned conditions. String failure will also occur if a single bulb, and its associated shunt, falls out of or is otherwise removed from its socket.
It would, therefore, be desirable to have a series circuit light string with a shunt system that is effective in preventing the failure of the entire light string when any one bulb is removed from its socket or when the bulb envelope and the single shunt therein is crushed or is otherwise broken. It would also be desirable to provide a shunt system effective in preventing the failure of the entire string should a single bulb become twisted within its socket.
It is an object of the present invention to provide a light string connected in a series circuit and having a bulb shunt system.
It is another object of the invention to provide a bulb shunt system in a series circuit light string wherein the shunt system is constructed to prevent the failure of the entire light string when any individual light bulb fails.
It is yet another object of the invention to provide a bulb shunt system for a light string wherein the shunt system includes multiple shunts with at least one shunt positioned outside of the bulb envelope.
It is still another object of the invention to provide a bulb shunt system that prevents the failure of the entire light string when individual bulbs on the string are removed, broken or are otherwise disconnected from the circuit.
These and other objects and advantages of the invention will be more fully appreciated by those skilled in the art upon the further consideration of the remaining disclosure, including the summary and the detailed description of the invention along with the associated drawings and the appended claims.